/*
 * Copyright (c) 2013-2017, ARM Limited and Contributors. All rights reserved.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */

#include <arch_helpers.h>
#include <assert.h>
#include <bl_common.h>
#include <context_mgmt.h>
#include <string.h>
#include <utils.h>
#include "opteed_private.h"

/*******************************************************************************
 * Given a OPTEE entrypoint info pointer, entry point PC, register width,
 * cpu id & pointer to a context data structure, this function will
 * initialize OPTEE context and entry point info for OPTEE.
 ******************************************************************************/
void opteed_init_optee_ep_state(struct entry_point_info *optee_entry_point,
                uint32_t rw, uint64_t pc,
                optee_context_t *optee_ctx)
{
    uint32_t ep_attr;

    /* Passing a NULL context is a critical programming error */
    assert(optee_ctx);
    assert(optee_entry_point);
    assert(pc);

    /* Associate this context with the cpu specified */
    optee_ctx->mpidr = read_mpidr_el1();
    optee_ctx->state = 0;
    set_optee_pstate(optee_ctx->state, OPTEE_PSTATE_OFF);

    cm_set_context(&optee_ctx->cpu_ctx, SECURE);

    /* initialise an entrypoint to set up the CPU context */
    ep_attr = SECURE | EP_ST_ENABLE;
    if (read_sctlr_el3() & SCTLR_EE_BIT)
        ep_attr |= EP_EE_BIG;
    SET_PARAM_HEAD(optee_entry_point, PARAM_EP, VERSION_1, ep_attr);
    optee_entry_point->pc = pc;
    if (rw == OPTEE_AARCH64)
        optee_entry_point->spsr = SPSR_64(MODE_EL1, MODE_SP_ELX,
                          DISABLE_ALL_EXCEPTIONS);
    else
        optee_entry_point->spsr = SPSR_MODE32(MODE32_svc, SPSR_T_ARM,
                              SPSR_E_LITTLE,
                              DAIF_FIQ_BIT |
                            DAIF_IRQ_BIT |
                            DAIF_ABT_BIT);
    zeromem(&optee_entry_point->args, sizeof(optee_entry_point->args));
}

/*******************************************************************************
 * This function takes an OPTEE context pointer and:
 * 1. Applies the S-EL1 system register context from optee_ctx->cpu_ctx.
 * 2. Saves the current C runtime state (callee saved registers) on the stack
 *    frame and saves a reference to this state.
 * 3. Calls el3_exit() so that the EL3 system and general purpose registers
 *    from the optee_ctx->cpu_ctx are used to enter the OPTEE image.
 ******************************************************************************/
uint64_t opteed_synchronous_sp_entry(optee_context_t *optee_ctx)
{
    uint64_t rc;

    assert(optee_ctx != NULL);
    assert(optee_ctx->c_rt_ctx == 0);

    /* Apply the Secure EL1 system register context and switch to it */
    assert(cm_get_context(SECURE) == &optee_ctx->cpu_ctx);
    cm_el1_sysregs_context_restore(SECURE);
    cm_set_next_eret_context(SECURE);

    rc = opteed_enter_sp(&optee_ctx->c_rt_ctx);
#if DEBUG
    optee_ctx->c_rt_ctx = 0;
#endif

    return rc;
}


/*******************************************************************************
 * This function takes an OPTEE context pointer and:
 * 1. Saves the S-EL1 system register context tp optee_ctx->cpu_ctx.
 * 2. Restores the current C runtime state (callee saved registers) from the
 *    stack frame using the reference to this state saved in opteed_enter_sp().
 * 3. It does not need to save any general purpose or EL3 system register state
 *    as the generic smc entry routine should have saved those.
 ******************************************************************************/
void opteed_synchronous_sp_exit(optee_context_t *optee_ctx, uint64_t ret)
{
    assert(optee_ctx != NULL);
    /* Save the Secure EL1 system register context */
    assert(cm_get_context(SECURE) == &optee_ctx->cpu_ctx);
    cm_el1_sysregs_context_save(SECURE);

    assert(optee_ctx->c_rt_ctx != 0);
    opteed_exit_sp(optee_ctx->c_rt_ctx, ret);

    /* Should never reach here */
    assert(0);
}
